Gas-phase polymerization of propylene: Reaction kinetics and molecular weight distribution

Meier, G. B.; Weickert, G.; Swaaij, W.P.M. van

doi:10.1002/1099-0518(20010215)39:4<500::aid-pola1019>3.0.co;2-s

Cited by 31 publications

(10 citation statements)

References 24 publications

(36 reference statements)

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“…Despite much research carried out in the field of the kinetics of olefin polymerization, in most cases, the kinetic constants are not estimated [27][28][29]. In some works, the evaluation of kinetic constants are based on polymerization time, average rate of polymerization, and final polymer characters [30][31][32], while in recent models, instantaneous reaction rates and final molecular weight of the resulting polymer have been used for estimation of kinetic parameters [26,[33][34][35][36][37][38][39].…”

Section: Introductionmentioning

confidence: 99%

Indirect Synthesis of Bis(2‐PhInd)ZrCl₂ Metallocene Catalyst, Kinetic Study and Modeling of Ethylene Polymerization

et al. 2011

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Bis(2-phenylindenyl)zirconium dichloride (bis(2-PhInd)ZrCl 2 ) catalyst was synthesized via the preparation of bis(2-phenylindenyl)zirconium dimethyl (bis(2-PhInd)ZrMe 2 ) followed by chlorination to obtain the catalyst. Performance of the catalyst for ethylene polymerization and its kinetic behavior were investigated. Activity of the catalyst increased as the [Al]:[Zr] molar ratio increased to 2333:1, followed by reduction at higher ratios. The maximum activity of the catalyst was obtained at a polymerization temperature of 60°C. The ratetime profile of the reaction was of a decay type under all conditions. A general kinetic scheme was modified by considering a reversible reaction of latent site formation, and used to predict dynamic polymerization rate and viscosity average molecular weight of the resulting polymer. Kinetic constants were estimated by the Nelder-Mead numerical optimization algorithm. It was shown that any deviation from the general kinetic behavior can be captured by the addition of the reversible reaction of latent site formation. Simulation results were in satisfactory agreement with experimental data.

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Section: Introductionmentioning

confidence: 99%

Indirect Synthesis of Bis(2‐PhInd)ZrCl₂ Metallocene Catalyst, Kinetic Study and Modeling of Ethylene Polymerization

et al. 2011

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“…It should be pointed out that when the catalyst feed rate is changed from 0.3 g/s to 0.4 gis, the constant bubble size model predicts a temperature above the accepted industrial safety limit of 80°C [10]. Working above this critical temperature may lead to particle agglomeration problems.…”

Section: A Effect Of Catalyst Feed Ratementioning

confidence: 99%

Different hydrodynamic model for gas-phase propylene polymerization in a catalytic fluidized bed reactor

Shamiri

Hussain

Mjalli

et al. 2010

2010 2nd International Conference on Chemical, Biological and Environmental Engineering

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A comparative simulation study was carried out using the improved well-mixed, constant bubble size and well mixed models. These fluidized bed reactor models, combined with comprehensive kinetics for propylene homo polymerization in the presence of a multiple active site Ziegler Natta catalyst. In the improved model, the effect of the presence of particles in the bubbles and the excess gas in the emulsion phase was taken into account to improve the quantitative understanding of the actual fluidized bed process. The superficial gas velocity and catalyst feed rate have a strong effect on the hydrodynamics and reaction rate, which results in a greater variation in the polymer production rate and reactor temperature. At typical operating conditions the improved well mixed and well mixed models were in good agreement. While the COO!ICU bubble size model was found to over-predict the emulsion phase temperature and under predict propylene concentration.

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“…Yet in situations involving catalysts of not so high activity, a Fickian diffusion mechanism (with estimated diffusivity values) continues to be employed, and perhaps considered satisfactory. But, as this fails to explain the high activity of lo5 g/g-cat h now attainable, the need for incorporating monomer convection in such a model is clear (McKenna et al, 1997;Weickert et al, 1999, Meier et al, 2001, McKenna and Soares, 2001. McKenna and Schweich (19921, McKenna et al (1995).…”

Section: Introductionmentioning

confidence: 99%

Modeling monomer transport by convection during olefin polymerization

Veera¹,

Weickert²,

Agarwal³

2002

AIChE Journal

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During olefin polymerization on heterogeneous catalyst, a catalyst particle undergoes fragmentation, and the formed polymer gets deposited on the fragments. These polymer-coated fragments (microparticles) together form a porous polymer particle (macroparticle). The multigrain model (MGM) gives a detailed description by accounting for the monomer diffusion phenomena at both levels. The original approach to solution involved a sequential shell-by-shell determination of monomer concentration profiles, with both radial boundaries of the shells moving with the particle growth. A fixed boundaly system of simultaneous differential equations enables easier computer implementation of the MGM model. Further, in a new development presented here, the interstitial spaces between the microparticles make up the pores through which monomer transport occurs not only by diffusion, but also by convection. The convection is driven by the pressure gradient created by the monomer consumption within the particle. Consistent with recent experimental observations, significantly higher monomer transport rates are thus predicted.Correspondence concerning this article should be addressed to U. S . Agdnval (Galvan and Tirrell, 1986). Then, we proceed to incorporate in this model an additional mode of monomer transport into the polymer particle, that is, monomer convection through the interconnected pores in the two-phase particle.During olefin polymerization on heterogeneous catalyst, the catalyst particle undergoes fragmentation and the polymer so formed gets deposited on the fragments. These polymercoated fragments (microparticles) together form a porous polymer particle (macroparticle). The overall reaction rate can be limited by the monomer transport, first through the porous macroparticle, and then within the microparticle (to the active sites on the catalyst fragments). The PFM, first proposed by Schmeal and Street (1971) and Singh and Merrill (1971), provides a simple description of the phenomena. It assumes the intraparticle mass transfer to be simply Fickian diffusion through the polymer. Galvan and Tirrell (1986) considered a mathematical transformation to convert the moving-boundary problem into a fixed-boundary problem.

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Gas-phase polymerization of propylene: Reaction kinetics and molecular weight distribution

Cited by 31 publications

References 24 publications

Indirect Synthesis of Bis(2‐PhInd)ZrCl₂ Metallocene Catalyst, Kinetic Study and Modeling of Ethylene Polymerization

Indirect Synthesis of Bis(2‐PhInd)ZrCl₂ Metallocene Catalyst, Kinetic Study and Modeling of Ethylene Polymerization

Different hydrodynamic model for gas-phase propylene polymerization in a catalytic fluidized bed reactor

Modeling monomer transport by convection during olefin polymerization

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Gas-phase polymerization of propylene: Reaction kinetics and molecular weight distribution

Cited by 31 publications

References 24 publications

Indirect Synthesis of Bis(2‐PhInd)ZrCl2 Metallocene Catalyst, Kinetic Study and Modeling of Ethylene Polymerization

Indirect Synthesis of Bis(2‐PhInd)ZrCl2 Metallocene Catalyst, Kinetic Study and Modeling of Ethylene Polymerization

Different hydrodynamic model for gas-phase propylene polymerization in a catalytic fluidized bed reactor

Modeling monomer transport by convection during olefin polymerization

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Indirect Synthesis of Bis(2‐PhInd)ZrCl₂ Metallocene Catalyst, Kinetic Study and Modeling of Ethylene Polymerization

Indirect Synthesis of Bis(2‐PhInd)ZrCl₂ Metallocene Catalyst, Kinetic Study and Modeling of Ethylene Polymerization